1. Field of the Invention
The present invention relates to a projector for projecting an image on a screen or the like and a protector for protecting the eyes of a person from projecting light emitted by the projector.
2. Description of the Related Art
Generally, a projector such as a liquid crystal projector for projecting an image on a screen located at a remote position is configured so as to emit projecting light by the use of a light source having a relatively high output (e.g., a halogen lamp or the like). Thus, Japanese Unexamined Utility Model Application Publication No. Hei 5-8556 proposes a projector comprising a sensor for detecting the presence or absence of an object (a person) in a space area (hereinafter referred to as a projection space area) which projecting light passes through for the purpose of preventing damage to the eyes of a person who carelessly looks into a projection lens or the like of the projector, wherein projection is stopped when the sensor detects an object in the projection space area.
In general, a person who gives an explanation of the image or the like is near the screen. The position at which the explaining person stands is the position having relatively low intensity even in the projection space area of the projector. Thus, the explaining person does not suffer damage to his/her eyes by the projecting light at the position. However, the above-mentioned projector described in Japanese Unexamined Utility Model Application Publication No. Hei 5-8556 may detect even the explaining person at the position and thus stop projecting. Therefore, the projector is disadvantageous for practical use.
The above-mentioned projector described in Japanese Unexamined Utility Model Application Publication No. Hei 5-8556 is designed so as to stop projecting only after detecting the entry of a person into the projection space area of the projector. However, the projector has a possibility that a person may look into the projection lens or the like before projection is stopped.
The present invention is designed to overcome the foregoing problems. It is an object of the present invention to provide a projector and the protector thereof having superior practicality and safety.
A projector according to the present invention comprises projecting means for projecting an image on a screen; detecting means for detecting the presence or absence of an object in an area to be subjected to detection, which is a local space near an outer edge of a projection space area which projecting light emitted from the projecting means passes through; and controlling means for performing control so as to reduce the intensity of the projecting light from the projecting means when the detecting means detects an object in the area to be subjected to detection.
More specifically, it is desirable that the area to be subjected to detection is located near the outer edge of the projection space area and extends along the outer edge of the projection space area.
A protector of a projector according to the present invention comprises detecting means for detecting the presence or absence of an object in an area to be subjected to detection, which is a local space near an outer edge of a projection space area which projecting light emitted from the projector passes through; and controlling means for performing control so as to reduce the intensity of the projecting light from the projector when the detecting means detects an object in the area to be subjected to detection.
In the projector or the protector thereof according to the present invention, the detecting means detects the passage of a person through the area to be subjected to detection before the person enters the projection space area, and the controlling means reduces the intensity of the projecting light from the projecting means. Therefore, the intensity of the projecting light is already reduced at the time when the person enters the projection space area. Moreover, the area to be subjected to detection is limited to the local space. Therefore, it is possible to prevent the detecting means from detecting an explaining person who stands near the screen, for example.